Sogard, wearing the horn-rimmed glasses that spawned a "Nerd Power" movement at O.co Coliseum, gave out the new spectacles and told kids how wearing glasses changed his life.

"I couldn't see without them, and I definitely wouldn't be as good a player," he said. "I want kids to know that even if they wear glasses, they can still play sports, get outside, be engaged. They don't have to feel weird."

The kids didn't need much convincing. Most of them have suffered from poor vision for years, but their parents can't afford, or are too swamped working multiple jobs, to arrange eye exams and buy frames.

The result is that the kids can't see the blackboard or have trouble reading, and fall behind.

That's where a Los Angeles nonprofit called Vision to Learn steps in. Founded in 2012, the group provides free eye exams and glasses to low-income kids in California, using a van outfitted as a mobile optometry clinic.

So far, the group has given out 16,000 pairs of glasses, in Southern California and Sacramento, with Tuesday's Oakland visit its first foray into the Bay Area.

About 15 percent of California schoolkids need glasses but don't have them, the group estimates.

"If you're a parent working a few jobs, taking four buses across town for an eye exam is cumbersome, to say the least," said Jamie Staugler, spokeswoman for Vision to Learn. "So we bring the eye doctor directly to the kids."

But the kids were the real stars. Joy Lumsey, a fourth-grader, said she loves to read but lately her head has started hurting.

"I read all the time, but it just makes my brain stressed," she said. "Now I'm getting glasses. I'm excited. Although I think it'll be weird."

Omar Ayala, a third-grader, said he thought the teacher was intentionally writing sloppily on the chalkboard.

Now he realizes he just couldn't see. His new glasses will change that.

"Now people are going to think I'm a nerd. But I'm not a nerd," he said. "Even though I'm smart."

Franklin, Oakland's biggest elementary school, also has one of its largest low-income populations. Principal Jeanette MacDonald said the new glasses will make a big difference for students, their families and the teachers.

"Words are not enough to say thank you," she told the Vision to Learn staff, Sogard and others. "Every time there's a boy or girl who can suddenly read, you'll all have our eternal gratitude."